The tile thing I did in 1195 turned out to be irrelevant to the issue (and caused other bugs), but I discovered that the real source of the slowdown is our view() code, which has a bearing on the map display (and will also affect the speed of any server routines that rely on view). We had a number of really horrible O(N^3) loops that were crying out for optimization.

Taking care of those loops, and adding some simple additional optimizations, made the demo responsive where it wasn't before, and faster where it was slow before. The view code was an issue because isometric necessarily has to visit more tiles for display.

This fix will be present in 499.1197. Your game still didn't perform great in the debugger when running client+server together, but when running just the client part it was much snappier.